Pigeons love brassicas...fact, whether its cabbage, cauliflower, sprouts whatever...if its in the brassica plant family then pigeons will gobble them up. Above is some cabbages planted side by side, one bed covered with a basic anti-bird netting, one uncovered and you can see the effects of wood pigeons after 1 night. Basic anti-bird and butterfly netting is easily sourced, such as here in Gardening-Naturally.com Cabbage and Butterfly Netting.